Merge pull request #1184 from Axelrod-Python/pin-prompt-toolkit-version

Pin prompt toolkit because of backwards comp.

Author: meatballs

requirements.txt

@@ -1,10 +1,10 @@
-numpy>=1.9.2
-matplotlib>=1.4.2
-tqdm>=3.4.0
-prompt-toolkit>=1.0.7
-scipy>=0.19.0
-hypothesis==3.2
+cloudpickle>=0.2.1
 dask>=0.11.0
+hypothesis==3.2
+matplotlib>=1.4.2
+numpy>=1.9.2
 pandas>=0.18.1
+prompt-toolkit>=1.0.7,<2.0.0
+scipy>=0.19.0
 toolz>=0.8.0
-cloudpickle>=0.2.1
+tqdm>=3.4.0